1. Field of the Invention
The present invention relates to a laser diode driver, and more particularly to a high power laser diode driver utilizing a monolithic semiconductor device capable of generating the high peak power, high pulse repetition frequency (PRF), laser pulses with pulse width of a few nanoseconds and significantly extending the capability of the diode driver.
2. Description of the Prior Art
We have already proposed a high power, high PRF, compact, pulsed laser diode driver in the pending U.S. patent application Ser. Nos. 08/215,228 and 08/215,287, both filed Mar. 31, 1994. This driver realizes utilization of the non-uniform impedance stripline as energy storage capacitor and optically activated semiconductor switch as high power switch. Such a utilization results in a highly efficient, extremely compact and highly capable laser diode driver circuit. In this scheme, the output pulse width of the high power laser diodes is determined by the two way wave transit time in the energy storage medium, namely, non-uniform impedance stripline. In an ideal operating condition, the output pulse width of the high power laser diodes is about two way wave transit time in the energy storage medium. Therefore, as the energy storage medium becomes smaller, the output pulse width of the laser light becomes short.
For the generation of the high peak power, high PRF, laser pulses with pulse width of a few nanoseconds, utilization of the non-uniform impedance stripline structure as the energy storage capacitor and optically activated switch as the high power switch is very effective way. However, due to practical reasons such as eye safety, effective distance, precision and high speed data communications, it is highly desirable to produce high peak power laser pulses with the narrowest pulse width. Therefore, for the generation of the high power laser light with narrow pulse width, the physical length of the energy storage medium has to be reduced. But as the physical length of the energy storage medium becomes very small, the effects of stray inductance and stray capacitance on the circuit performance become very serious. As a consequence, there will be severe degradation on the pulse rise and fall times as well as the pulse amplitude.
Hence, merely reducing the physical length of the energy storage medium may not produce high current pulses with pulse width less than a few nanoseconds. The stray inductance as well as the stray capacitance at interconnections have to be minimized.